Epoxy composition

Abstract

A composition suitable for making circuitboards containing two different brominated epoxy polymeric components which are brominated diglycidyl ethers of bisphenol-A and epoxidized nonlinear novolak having at least about six terminal epoxy groups.

What is claimed is: 
     
       1. A composition of matter comprising: (A) about 25 to about 30 parts by weight of a tetrabrominated diglycidyl ether of bisphenol-A having an epoxy equivalent weight of about 350 to about 450;   (B) about 10 to about 15 parts by weight of a second and different tetrabrominated diglycidyl ether of bisphenol-A having an epoxy equivalent weight of about 600 to about 750; and   (C) about 55 to about 65 parts by weight of at least one epoxidized non-linear novolak having at least six terminal epoxy groups.   
     
     
       2. The composition of claim 1 wherein said novolak has at least eight terminal epoxy groups. 
     
     
       3. The composition of claim 1 wherein said novolak has the average formula: ##STR7## 
     
     
       4. The composition of claim 1 wherein (A) has an epoxy equivalent weight of about 400 and (B) has an epoxy equivalent weight of about 650. 
     
     
       5. The composition of claim 1 which contains about 28 parts by weight of (A); about 12 parts by weight of (B); and about 60 parts by weight of (C). 
     
     
       6. The composition of claim 5 wherein (A) has an epoxy equivalent weight of about 400; and (B) has an epoxy equivalent weight of about 650. 
     
     
       7. The composition of claim 1 which further includes an organic diluent. 
     
     
       8. The composition of claim 7 wherein said organic diluent is present in an amount of about 90 to about 120 parts by weight per hundred parts of the total of (A), (B), and (C). 
     
     
       9. The composition of claim 7 wherein said organic diluent is present in an amount of about 100 to about 116 parts by weight. 
     
     
       10. The composition of claim 7 wherein said organic diluent is a ketone. 
     
     
       11. The composition of claim 10 wherein said ketone is methylethyl ketone. 
     
     
       12. The composition of claim 1 which contains about 27 to about 29 parts by weight of (A); about 11 to about 13 parts by weight of (B); and about 58 to about 62 parts by weight of (C).